1. Field of the Invention
The present invention relates to a reticle-carrying container for carrying a reticle used for a light exposure apparatus or the like that transfers a set pattern to a substrate.
2. Description of the Background Art
Semiconductor devices and liquid crystal display devices are manufactured in process of photolithography. In this process, an image of pattern formed on a reticle (including a photo mask) is projected and transferred by a light exposure apparatus onto a substrate such as a semiconductor wafer and a glass plate. At that time, the transferred pattern reacts with a photosensitive agent applied to the substrate, and then a circuit is formed through the subsequent operations.
During this process, a reticle is stored in a dedicated reticle-carrying container in order to prevent contamination with dust, etc. and damage from contact with other components.
For making an intricate circuit, it is necessary to provide a large number of circuit patterns on the substrate. Accordingly, many reticles are prepared and many patterns are formed in layers on the substrate.
FIG. 2 shows one example of an apparatus used in the photolithography process. In the figure, a numeral number 1 indicates a light exposure apparatus that projects and transfers a circuit pattern onto the substrate. A numeral number 2 denotes a reticle stocker in which a large number of reticles are stored and retained. A numeral number 3 shows a reticle-carrying container which stores reticles. A numeral number 4 indicates a transfer rail provided between a light exposure apparatus 1 and a reticle stocker 2, which transfers the reticles stored in a reticle-carrying container 3 between these two components. A numeral number 5 shows a transfer mechanism provided on the transfer rail 4, which holds and transfers directly the reticle-carrying container 3.
These components are controlled by a controller (not shown). With this, the reticles required for a circuit pattern stored in the reticle-carrying container 3 are transferred by the transfer mechanism 5 on the transfer rail 4 from the reticle stocker 2 to the light exposure apparatus 1. The reticles no longer required in the light exposure apparatus 1 are returned to the reticle stocker 2 by the transfer mechanism 5 on the transfer rail 4.
The reticles used in the above described process are precision components. If the reticles are contaminated with dust, etc. or damaged by contact with other components, it is impossible to form an accurate circuit pattern. Therefore, various kinds of reticle-carrying containers 3 for supporting the reticles safely and securely have been suggested so far.
One example is shown in a patent document 1(Japanese Patent Laid-open No. 10-163094). The reticle supporting means set forth in the patent document 1 is a pin. As means for supporting a reticle from underneath, the reticle supporting pins are provided on the four corners of the reticle. In addition, as means for supporting a reticle from its periphery so as not to be shifted in a horizontal direction, the stopper pins for preventing a horizontal movement are provided. Moreover, as means for supporting a reticle from above, the reticle retainer is provided. These means support and fix the reticle in X, Y and Z directions.
Additionally, a pellicle may be attached to the reticle. In this case, a pellicle-carrying container may be utilized. For the pellicle-carrying container as well, various kinds of pellicle-carrying containers for supporting a pellicle safely and securely have been proposed so far.
One example is described in a patent document 2 (Japanese Patent Laid-open No. 10-17051). The pellicle supporting means set forth in the patent document 2 are a projected line and an elastically deforming member. As means for supporting a pellicle from underneath, the projected line and the elastically deforming member are provided in the positions corresponding to the peripheral edge of the pellicle. In addition, as means for supporting a pellicle from its periphery so as not to be shifted in a horizontal direction, an engagement portion for preventing a horizontal movement are provided. Moreover, as means for supporting a pellicle from above, a portion of the lid is provided as a tapered retaining portion. These means support and fix the pellicle in X, Y and Z directions.
However, the above described reticle-carrying container has such a structure in which the highly rigid pins contact and support directly the lower side and upper side of the reticle. This causes the vibrations of the reticle-carrying container to be conveyed directly to the reticle, which is undesirable in treating a precision component.
In addition, since the member for supporting the lower side of the reticle has a flat surface, the reticle may be shifted in a horizontal direction due to vibrations, etc. from outside. Also, there is a gap between the stopper and the peripheral edge of the reticle, and thus the reticle may be shifted in a horizontal direction within the range of this gap.
As the circuit becomes higher in density and more complicated, the reticle would be increased in the degree of precision. Therefore, it is desired to treat the reticle more carefully.
Likewise, it is desired to handle the pellicle more cautiously so as to have no harmful effects on the reticle.